"A vehicle was broken into -- a window was smashed, and a purse was taken," Waukesha County Sheriff's Office Detective Jack Kopatich said. "Within a short time after, the credit cards that were stolen were actually being used."

Authorities are investigating four cases at Woodside Elementary and Maple Elementary in Sussex and two places in Oconomowoc.

Kopatich said the same man was caught on surveillance video at each crime scene, and law enforcement knows him.

"He is actively wanted on violation of parole. I believe he's wanted on parole for fraud," Kopatich said. "His name is Calvin Walker, born in 1976. We believe he resides on the north side of Milwaukee."

Kopatich said Walker goes by a number of names.

"From what I could count, at least 18 different aliases," Kopatich said.

The school district has sent a note to parents. Anyone with information about the investigation should contact the Waukesha County Sheriff's Office.

A Mexican photojournalist who left the state he worked in because of threats was among five people found shot to death in a Mexico City apartment this weekend, officials and press freedom advocacy groups said.